ModBus Interface
iTrans Fixed Point Single/Dual Gas Monitor
6-10
INDUSTRIAL SCIENTIFIC
(P/N: 77023554)
NOTE:
If adding a second sensor to an existing module, set the ModBus address
to
which represents 11110000 binary (and 240 decimal). See
Chapter 6 for more information on the ModBus interface. (Note that DIP switches
are pre-set at the factory for all dual-sensor units).
6.7. ModBus Resources
ModBus is a public protocol that can be freely adopted by any developer or
manufacturer desiring to implement it. While a detailed discussion of ModBus
protocol is beyond the scope of this manual, there are a number of up-to-date
resources available on the internet for those wishing to investigate ModBus further.
The most complete resource is www.modbus.org.
6.8. Termination
When putting devices on the ModBus network, a terminating resistor may be
required for the last device on the network (please see www.modbus.org for more
details). The
has a blue jumper on the “public” jumper that can be used
to jumper in a 120-Ohm terminating resistor. By default, this jumper is not in
place. Industrial Scientific does not recommend changing the placement of any of
the other jumpers on this board.
Figure 6-
5
. Location of Jumpers
Summary of Contents for iTrans 77023554
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